REVULSION over photos of child victims of an alleged chemical weapons attack in Syria left the White House facing new calls for a firm response Thursday.

Republican Senator John McCain warned US President Barack Obama had given Syria President Bashar al-Assad a "green light'' to commit atrocities by failing to use military force to respond to previous attacks.

The White House said it was appalled by reports of an attack which rebels said killed 1300 people outside Damascus, and renewed calls for Syria to allow a UN probe.

Mr McCain has been a frequent critic of Mr Obama's reluctance to commit US military forces to protect civilians in Syria, and bemoaned the horror of the latest attack.

"When the president of the United States says that if he uses these weapons that it would be a, quote, 'red line and a game-changer,' (Assad) now sees that as a green light,'' he told CNN. "The word of the president of the United Sates can no longer be taken seriously, as it isn't throughout the entire region.''

MR McCain said that in a "couple of days'' US air power could take out Syrian air force runways and up to 50 aircraft being used to dominate battlefields against rebels.

"We can supply the right kind of weapons to rebels, establish a no-fly zone by moving Patriot missiles up to the border. This can be done very easily.''

White House spokesman Josh Earnest said the administration was horrified by the latest reports.

"The images that we have seen are nothing short of horrifying,'' he said.

He repeated a US call for Syria's government to permit a United Nations team already in the country to probe previous alleged chemical attacks to examine the new claimed outrage.

Shocking pictures of dead children blanketed the front pages of US newspapers and were shown on cable news shows Thursday, subjecting the White House Syria policy under new scrutiny.

The Wall Street Journal cited an unnamed official as saying there were "strong indications'' that Syrian government forces had carried out a chemical weapons attack. The White House declined to confirm that statement, and has said it is seeking to verify the reports.

Damascus has vehemently denied it unleashed chemical weapons on rebel-held area outside Damascus.

If confirmed, the attack would be the largest scale use of chemical weapons since Saddam Hussein's Iraqi forces attacked the Kurdish town of Halabja in 1988.

On Wednesday, the White House refused to say that if the attack was proven it would represent another violation of US "red lines'' for Syria

Officials said on Wednesday that Washington did in fact respond to the previous use of chemical weapons in Syria by offering military aid to rebels for the first time.

The top US military officer General Martin Dempsey also warned the use of force in Syria could end up embroiling Washington in an open-ended war in the country.

Earlier, France threatened the international community will use armed force against Syria if the chemical massacre is confirmed.

French Foreign Minister Laurent Fabius said if the United Nations Security Council was unable to make a move, "decisions will be taken in other ways".

"If this is proven, France's position is that there must be a reaction," Mr Fabius told French television network BFM.

"There would have to be a reaction with force in Syria from the international community, but there is no question of sending troops on the ground."

Meanwhile, AFP reports German Foreign Minister Guido Westerwelle and his Turkish counterpart Ahmet Davutoglu have held a press conference in Berlin. Mr Davutoglu said a "red line was crossed" in Syria and called for international action following reports of a massacre involving chemical weapons.

"All red lines have been crossed but still the UN Security Council has not even been able to take a decision. This is a responsibility for the sides who still set these red lines and for all of us," Davutoglu told reporters in Berlin.

Syria is under intense pressure to allow UN weapons inspectors into the site which the opposition says left hundreds dead and provoked revulsion around the world.

EDITOR'S NOTE: Here at News.com.au, we're well aware that images of the victims of the Syrian gas attack - particularly children - will distress many readers. We don't take the decision to publish these pictures lightly. But as the editor, I don't resile from it either. The more such images are censored, the less reason there is for the world to sit up and pay attention to the horror show which is playing out in Syria daily. If you feel you don't need to look at the pictures, please don't click on the gallery marked with a warning. - Luke McIlveen

CLICK BELOW FOR GRAPHIC IMAGES FROM SYRIAN MASSACRE

Damascus has flatly denied the allegations but a US official cited by the Wall Street Journal said on Thursday there were "strong indications" regime forces had indeed unleashed chemical weapons during attacks the previous day on rebel zones near the capital.

The National Coalition said more than 1300 people had died while videos and photographs showed scenes of people foaming at the mouth and of bodies stacked up in morgues.

In one video posted on YouTube, children are seen receiving first aid in a field hospital, notably oxygen to help them breathe. Doctors appear to be trying to resuscitate unconscious children.

Another video showed what activists said was a case of hysteria following a chemical strike in the eastern suburbs. The authenticity of the videos has not immediately been verified.

A Syrian girl in shock screams in Arabic "I am alive" following an attack in which Syrian opposition claim the regime used chemical weapons in eastern Ghouta, on the outskirts of Damascus. The image grab taken from a video uploaded on YouTube by the Arbeen unified press office on August 21, 2013. It has not been independently verified.

A young girl held her head in her hands and frantically repeated "I'm alive'', as a man in a white coat tried to comfort her.

The Syrian Observatory for Human Rights reported that Syrian forces on Thursday bombed and shelled a number of rebel zones where the Coalition alleged the attacks took place the previous day.

Western governments demanded immediate access for a team of UN inspectors already in Syria to probe previous allegations of chemical weapons strikes to the sites of the alleged attacks.

The head of the UN inspection mission, Aake Sellstroem, was in talks with Damascus "on all issues pertaining to the alleged use of chemical weapons, including this most recent reported incident," a UN statement said.

There are claims thousands of people have been killed in a Syrian army chemical weapon bombardment.

White House spokesman Josh Earnest demanded the inspectors be given "immediate access to witnesses and affected individuals" and "the ability to examine and collect physical evidence without any interference or manipulation from the Syrian government."

Washington has previously described chemical weapons use as a red line that might prompt it to intervene militarily in Syria.

The Wall Street Journal reported a senior administration official as saying the claims of a chemical weapons attack appeared to have some credibility.

"There are strong indications there was a chemical weapons attack - clearly by the government," the unnamed official said.

A handout image released by the Syrian opposition's Shaam News Network shows a woman mourning over a body wrapped in shrouds laid out in a line on the ground with other victims which Syrian rebels claim were killed in a toxic gas attack by pro-government forces.

"But we do need to do our due diligence and get all the facts and determine what steps need to be taken."

Human rights groups backed calls for access for the UN inspectors to the sites of the alleged attacks.

Should the allegations be true, "the attacks would amount to war crimes," said Amnesty International's deputy director for the Middle East and North Africa Hassiba Hadj Sahraoui, who urged the UN inspectors to visit the site.

The UN inspectors arrived in Damascus on Sunday with a strict mandate to investigate three sites for the alleged use of chemical weapons.

This citizen journalism image provided by the Local Committee of Arbeen which has been authenticated based on its contents, shows a Syrian girl receiving treatment at a makeshift hospital in Arbeen town, Damascus after an alleegd toxic gas attack. (AP Photo/Local Committee of Arbeen)

A high-ranking Syrian security source described the idea that the army would use chemical weapons while UN weapons inspectors were working inside the country as "political suicide".

The opposition National Coalition's George Sabra said more than 1300 people had been killed in what he "The Syrian regime is mocking the UN and the great powers when it strikes targets near Damascus, while the (UN weapons inspectors) are just a few steps away,'' the opposition National Coalition's George Sabra said, describing the attack as a "coup de grace that kills all hopes for a political solution in Syria''.

Prime Minister Kevin Rudd says news of the massacre in Syria is "repugnant" and he wants United Nations weapons inspectors to investigate.

"The use of weapons of mass destruction in any circumstances is intolerable and unacceptable in any civilised nation," Mr Rudd told reporters in Victoria on Thursday.

In this citizen journalism image provided by the Local Committee of Arbeen, a man and woman mourn over the dead bodies of Syrian men after an alleged poisonous gas attack fired by regime forces that killed 1300 people, including many children. Picture: AP

"When weapons of mass destruction, including chemical weapons, are used against civilian targets it is repugnant beyond description."

Following an emergency meeting of the UN Security Council in New York, the council's president, Argentina's envoy Maria Cristina Perceval, said: "There must be clarity on what happened and the situation must be followed carefully.''

She added that members "welcomed the determination of the secretary general to ensure a thorough, impartial and prompt investigation''.

The 15-nation body expressed "strong concern'' about the allegations and agreed that any chemical weapons use is "a violation of international law''.

A handout image released by the Syrian opposition's Shaam News Network shows people inspecting bodies of children and adults laying on the ground as Syrian rebels claim they were killed in a toxic gas attack.

The US, Britain and France demanded that a team of UN experts already in the country be granted immediate access to investigate the claims.

Videos and photographs showed row upon row of bodies wrapped in white shrouds lying on a tile floor, including many children. There was little evidence of blood or conventional injuries and most appeared to have suffocated.

A pharmacist who treated victims said: "Their mouths were foaming, their pupils were constricted, and those who were brought in while still alive could not draw their breaths and died subsequently."

Survivors, some twitching uncontrollably, lay on gurneys with oxygen masks covering their faces.

Citizen journalism image provided by Aleppo Media Center AMC which has been authenticated shows a Syrian boy holding an Arabic placard that reads: "if Syria's children bled petrol, the entire world would have intervened," during a demonstration against the alleged chemical weapons attack at the suburbs of Damascus. (AP Photo/Aleppo Media Center, AMC)

UN Secretary General Ban Ki-moon's office said he was "shocked'' by the reports and that UN weapons experts in Syria to probe previous allegations were in discussions with Damascus.

Security Council members France, Britain, the United States, Luxembourg and South Korea requested the meeting, which was held behind closed doors.

Britain, France, Germany and the United States sent a formal request for an investigation of the incident to Ban's office, citing ''credible reports of the use of chemical weapons'' in a letter.

Western governments demanded immediate access for the inspectors to investigate the new allegations. Russia, a longstanding ally of the Damascus regime, echoed the call for an inquiry but said it suspected a ''provocation'' by the opposition and its foreign backers.

Syria has denied opposition claims that chemical attacks on several Damascus suburbs killed 1,300 people including children. Mana Rabiee reports.

The White House said it's "deeply concerned" about reports that chemical weapons were used by Syria's government against civilians.

The allegations of gassing civilians dwarfed all previous such accounts in the increasingly bloody civil war.

The Syrian Network for Human Rights reported that 647 Syrians were killed in the attacks, and it attributed nearly 590 of those deaths to chemical weapons.

The Syrian Observatory for Human Rights, considered the most authoritative group tracking casualties in the conflict, estimated at least 136 dead from an air assault but didn't address whether chemical weapons appeared to be involved.

A Syrian military soldier holds his AK-47 with a sticker of Syrian President Bashar Assad and Arabic that reads, "Syria is fine." Syrian opposition groups claimed scores have died in which some activists say regime troops used "poisonous gas."

Observatory director Rami Abdul-Rahman cited activists in the area who said "poisonous gas'' was fired in rockets as well as from the air. He said that he had documented at least 136 deaths, but said it was not clear whether the victims died from shelling or toxic gas.

The Local Coordination Committees activist group said hundreds of people were killed or wounded. The Syrian National Coalition, the main Western-backed opposition group in exile, put the number at 1300, basing its claim on accounts and photographs by activists on the ground.

Syria is said to have one of the world's largest stockpiles of chemical weapons, including mustard gas and the nerve agent sarin.

Jean Pascal Zanders, an independent researcher who specialises in chemical and biological weapons and disarmament, said that in videos of the aftermath of the attacks, the hue of the victims' faces appeared to show many suffered from asphyxiation.

However, he said the symptoms they exhibited were not consistent with mustard gas or the nerve agents VX or sarin.

Mustard gas would cause blistering of the skin and discoloration, while the nerve agents would produce severe convulsions in the victims and also affect the paramedics treating them - neither of which was evident from the videos or reports.

"I'm deliberately not using the term chemical weapons here,'' he said. "There's plenty of other nasty stuff that was used in the past as a chemical warfare agent, so many industrial toxicants could be used too.''

A pharmacist in the town of Arbeen who identified himself as Abu Ahmad said he attended to dozens of wounded people in a field hospital after the shelling on Zamalka and Ein Tarma early Wednesday. He said many were moved to Arbeen.

The bodies of 63 of the dead had signs of a chemical weapons attack, he said, though he could not confirm this.

"Their mouths were foaming, their pupils were constricted, and those who were brought in while still alive could not draw their breaths and died subsequently,'' he told The Associated Press via Skype.

"The skin around their eyes and noses was grayish.''

Activists in nearby Zamalka told Abu Ahmed that an additional 200 people died in that town on Wednesday.

Syria's information minister, Omran al-Zoubi, denied government troops used chemical agents, calling the activists' claim a "disillusioned and fabricated one whose objective is to deviate and mislead'' the U.N. mission.

The head of the U.N. team, which has a mandate to investigate previous claims of alleged chemical attacks, said he wants to look into the latest claims.

Speaking to Swedish broadcaster SVT, Ake Sellstrom said the high numbers of dead and wounded being reported "sound suspicious.''

"It looks like something we need to look into,'' Sellstrom, who is Swedish, was quoted as saying.

He said a formal request from a member state would have to go through U.N. channels and Syria would need to agree - and there is no guarantee that it would.

Ghazwan Bwidany, a doctor treating the injured, told the BBC the main symptom, especially among children, was suffocation, as well as salivating and blurred vision.

"We don't have the capability to treat all this number of people," he said.

Opposition sources accused the army of multiple chemical weapons strikes -- one in Moadamiyet al-Sham, southwest of Damascus, and more in the capital's eastern suburbs.

The Local Coordination Committees (LCC), a network of activists, reported hundreds of casualties in the "brutal use of toxic gas by the criminal regime''.

And in videos posted on YouTube, the Syrian Revolution General Commission, another activist group, showed what it called "a terrible massacre committed by regime forces with toxic gas.''

In one video, children are seen being given first aid in a field hospital, notably oxygen to help them breathe. Doctors appear to be trying to resuscitate unconscious children.

Other images - distributed by the oppisition Shaam News Network - show lines of uncovered bodies, many of them children.

Specialists in the impact of chemical weapons said the video evidence was not entirely convincing.

"At the moment, I am not totally convinced because the people that are helping them are without any protective clothing and without any respirators,'' said Paula Vanninen, director of Verifin, the Finnish Institute for Verification of the Chemical Weapons Convention.

"In a real case, they would also be contaminated and would also be having symptoms.''

John Hart, head of the Chemical and Biological Security Project at Stockholm International Peace Research Institute said he had not seen the telltale evidence in the eyes of the victims that would be compelling evidence of chemical weapons use.

"Of the videos that I've seen for the last few hours, none of them show pinpoint pupils... this would indicate exposure to organophosphorus nerve agents,'' he said.

State news agency SANA said "reports on the use of chemical weapons in Ghouta (the Damascus suburbs) are totally false. It's an attempt to prevent the UN commission of inquiry from carrying out its mission.''

The UN Security Council met to discuss the allegations as UN officials said that talks were already under way with President Bashar al-Assad's government on securing access to the alleged attack sites.

The head of the UN inspection mission, Aake Sellstroem, was ``in discussions with the Syrian government on all issues pertaining to the alleged use of chemical weapons, including this most recent reported incident,'' a statement said.

Washington demanded that the inspectors be given unfettered access.

"For the UN's efforts to be credible, they must have immediate access to witnesses and affected individuals, and have the ability to examine and collect physical evidence without any interference or manipulation from the Syrian government,'' said White House spokesman Josh Earnest.

Washington has previously described chemical weapons use as a red line that might prompt it to intervene militarily in Syria.

British Foreign Secretary William Hague said: "I hope this will wake up some who have supported the Assad regime, to realise its murderous and barbaric nature.''

Moscow, which has said it has proof of chemical weapons use by the rebels in March, expressed scepticism about the opposition's claims.

The foreign ministry said the timing of the allegations as UN inspectors began their work "`makes us think that we are once again dealing with a premeditated provocation.''

The heavy bombing on the outskirts of the capital could be heard by residents of Damascus, where a grey cloud capped the sky.

The Britain-based Observatory, which relies on a vast network of activists on the ground and medics, said the army operation was aimed at the recapture of Madhamiyat el-Sham, an area southwest of Damascus.

The Syrian Observatory called for inspectors to hastily visit the stricken sites and ensure access for medical aid.

UN chief Ban Ki-moon insisted Monday that the inspectors be granted unrestricted access to Syrian sites where chemical weapons have allegedly been used in the country's 29-month-old conflict.

The inspectors, expected to visit three sites including Khan al-Assal near Aleppo in the north, are due to be in Syria for 14 days, with the possibility for an extension of the mission.

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Comments on this story

Chris W. of Brisbane Posted at 1:47 PM August 22, 2013

I was expecting a wave of anger towards the Assad government based on this news report. I must say I'm pleasantly surprised that a lot of people are not fooled by yet could be another display of Western media portraying these events for the benefit of the so called freedom fighters backed by the West. If the West has nothing to gain from this, would they still intervene? All they want is to install another puppet and turn the Middle East into "Middle America". Well done readers.

John Posted at 1:46 PM August 22, 2013

False flag....The US have been itching to invade and now they will. Simple.

Silent Posted at 1:41 PM August 22, 2013

If biological warfare has been used in Syria, Western Governments are going to intervene. If it is revealed that this was a biological attack, America is going to step in and take out the enemy - or rather, the enemy their world leaders want the world to think exist.
This is going to become a second Iraq soon. And hopefully, whoever our next leader is is smart enough to not get involved this time.

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